alosetron, Lotronex

Omudhome Ogbru, PharmD

Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

GENERIC NAME: alosetron

BRAND NAME: Lotronex

DRUG CLASS AND MECHANISM: Alosetron is used to treat diarrhea and abdominal discomfort that occurs in some women with irritable bowel syndrome (IBS). It works in a similar fashion as granisetron (Kytril), ondansetron (Zofran) and dolasetron (Anzemet) that are used for preventing nausea and vomiting. The discomfort and diarrhea of IBS is believed to be due to abnormal activity of the muscles of the intestines and/or the nerves that control the muscles. One of the chemical messengers which is important in coordinating the activity of intestinal nerves is serotonin. (Chemical messengers are chemicals produced and released by nerve cells that and cause changes in the activity of other nerve cells.) Alosetron belongs to a class of drugs that block one type of serotonin receptor called the 5-HT3 receptor. Serotonin and its receptors in the intestines may control pain sensation, contraction of intestinal muscle, and release of fluid into the intestines. These actions of serotonin can result in pain and diarrhea. The exact cause of IBS is unknown, but it is thought that stimuli such as food, medications, hormonal changes, or stress may trigger an excessive release or excessive response to serotonin. This may cause pain, and diarrhea seen in patients with diarrhea-predominant IBS. Alosetron, by blocking 5-HT3 receptors, reduces the actions of serotonin. Alosetron (Lotronex) was approved for marketing by the FDA in February, 2000 but was withdrawn from the market in November 2000, because of serious, life-threatening, gastrointestinal side effects. In June 2002, it was approved again by the FDA for marketing but in a restricted manner as part of a drug company-sponsored program for managing the risks associated with treatment. Use of alosetron is allowed only among women with severe, diarrhea-predominant IBS who have failed to respond to conventional treatment for IBS.